Spacers are purely for clearance. Purely for the fact that you didn't lengthen the spring so it can't flex any more than before. I mean it is still the same spring. I installed the teraflex 1.5" spacer kit. 2" front 1" rear with new rear sway bar links. Like $130 and some change. It leveled it and looks great. I did it on a 14' Sahara. And it didn't change on road performance one bit. With the proper back spacing you can run a 35" on a stock jk and not rub. A 1.5" spacer lift won't make that much of a difference. I wouldn't recommend running any larger than a 35" with that setup. And make sure if you go much wider to get a different wheel with proper back spacing.